Born in what was then the British colony of Boston, Massachusetts, on January17, 1706, Franklin was the fifteenth of seventeen children and received onlytwo years of a formal education. He started working in his father's candlemaking shop at the age of ten and later became an apprentice printer, working for his brother James. As a printer he developed a love for books, from whichhe educated himself. He spent two years in London, where he learned more about printing, and returned to Philadelphia in 1726. There he established the Pennsylvania Gazette and Poor Richard's Almanack, which earned him a tidy income. Franklin's first major invention, around 1740, was the Pennsylvania fireplace, which eventually became known as the Franklin stove. Improving on an existing design, the Franklin stove had a flue around which room air could circulate. The flue acted like a radiator, increasing heating efficiency. Franklinclaimed it made a room twice as warm, with one-quarter of the wood.
In 1746 Franklin had witnessed a public demonstration of electricity, and hisinterest was piqued. It is for his work in this subject that he became mostfamous. In the demonstration, a machine was used to generate static electricity which was stored in a Leyden jar (a water-filled bottle with a stopper through which a metal rod extended). People were instructed to join hands, forming a "circuit," and they simultaneously received a shock from the jar.
Investigating electric phenomena was all the rage, especially in Europe, butnot one of the learned scientists had thought to ask the simple question Franklin framed: "How does it work?" He decided to obtain a jar of his own and find out. Franklin charged his jar, poured the water into another bottle, and found it had lost its charge. If the water did not hold the charge, it indicated that the glass of the jar did. To see if that was the case, he took a window pane, placed a thin sheet of lead on each side, and gave it a charge. He removed the sheets and tested for an electric charge. The glass sparked but nocharge was indicated. Inadvertently, Franklin had just invented the electrical condenser. The condenser, also known as a capacitor, was destined to be one of the most important elements in electric circuits. Today the condenser, which received its name from Alessandro Volta , is used in radios, televisions, telephones, radar systems, and many other devices.
Drawing a parallel between the sparking Leyden jar and lightning, Franklin began to speculate that the sky might have an electrical charge. To "collect "this charge, he hit upon the idea of erecting a long metal rod on the top ofChrist Church in Philadelphia. The rod would conduct electricity to a man onan insulated platform in a sentry box, who could collect the charge in a Leyden jar. Unfortunately, before the rod could be attached to the church, a French scientist named D'Alibard, who had read of Franklin's work, successfully performed the experiment himself on May 10, 1752. Franklin, always the diplomat, generously gave D'Alibard credit for being the first to " draw lightning from the skies."
Was D'Alibard really the first? While waiting for the installation of the lightning rod , Franklin thought of a quicker way to get a conductor in the sky.Yes, he really did fly a kite in a thunderstorm! He was fortunate lightningdid not actually strike his kite because he would have been killed. Two otherscientists who duplicated the experiment suffered this fate. Whether D'Alibard was the first to "draw lightning" or not is irrelevant; it is Franklin that history remembers as being the inventor of the lightning rod.
The lightning rod became indispensable for protecting buildings from the destructive force of lightning. Because he had discovered he could get the Leydenjar to spark over a greater distance with a sharply pointed rod, Franklin'slightning rods had very sharp points. (In 1776, after the unpleasantness between the Colonies and King George III had broken out, the king ordered that lightning rods with blunt ends be installed on his palace.) By 1782 there were four hundred lightning rods in Philadelphia.
Franklin's work with electricity led him to coin numerous terms and propose several theories. Battery , conductor, condenser, armature, electrician, charge, and discharge are some of the words attributed to Franklin. He came up with the idea of "positive" and "negative" electricity having "plus" and "minus"charges. He incorrectly thought electric flow was from positive to negative;the opposite is true.
To say Franklin was involved in politics is a great understatement. He established service organizations, was Postmaster of Philadelphia, and founded a college that eventually became the University of Pennsylvania. He returned to London in 1757 as an Agent of the Pennsylvania Assembly and remained there nearly 18 years. In 1775 he returned and joined the committee drafting the Declaration of Independence. While in France after the Revolutionary War, eighty-three year old Franklin came up with yet another innovation: bifocal lenses. He had become frustrated with having to continually change his glasses for reading up close or seeing at a distance and came up on the idea of mounting half of each lens in a single frame. Franklin is also credited with inventing the rocking chair, the glass harmonica, the concept of daylight savings time, and the first public library. On April 17, 1790, Franklin died in Philadelphia.